How to smooth camera animation to have fluid feel?
A way to achieve camera motion with fluid non-synthetic feel is with softbody camera rig. This will do automatic easing of any motion and will save some graph-editor work.


Create a filled Circle with 3 vertices, subdivide it and delete the middle face:


Create new empty vertex group, don't assign any vertices to it, leave it empty:


Add camera to the scene and parent it to the 3 inner vertices (select Camera, select Mesh, enter edit-mode, select vertices, Ctrl+P):


Add Soft Body to the mesh object. These are the settings to take care of:


Friction: higher will be more lazy smoother camera
Damping: less means more camera jiggle and more overshoot



Its good to hide the Soft Body modifier visibility when animating. Always bake the softbody cache. This is a result of a simple linear-interpolation animation with just 2 keyframes, you can see how the soft body smooths everything:


Best it's in combination with follow path animation to smooth any paths and timing discontinuities. Use the Follow Path constraint on the softbody to animate the location (animate evaluation time under the curve) and Track To constraint or just keyframes for the softbody rotation.


The resulting camera motion will be the curve smoothed, so even when the curve itself is not C2 smooth the resulting animation will be. This can't be done in graph editor or with smoothing the curve with smooth modifier (it follows the un-smoothed curve)